Vacuum apparatus.



E. WEINTRAUB.

VACUUM APPARATUS.

APPLICATION FILED 1150.43, 1910.

Patented Sept. 3, 1912.

lnven tor Witnesses 'Ezechel Weintraub His Attorney.

' tiiiers, or, at a very UNlllll,

rastrear EZECHE'L WENTRAUB, 0F LYNN, MASSACHUSETTS, ASSIGNOR T0 GENERJ ELECTR'C GGMPANY, A. COROBATION OF NEW YORK.

VCUUM APPARATUS.

inerme.,

Specification. of Letters Patent.

Patented Sept.. 3, 1912..

Application filed December i3, 1910. Serial No. 597,011.

seals or closures ,tor vacuum apparatus, particularly electrical devices suchas vapor rectifier-s and lamps, and it is particularly applicable to devices consisting; ci a material such as fused silica. The use or" fused quartz or silica a material jor the envelop ot vaporelectric and similar devices, permits running Lhese devices at a very high current density, 'thereby increasing' the current carryingA capacity in the case ot rechigh temperature, im* proving the efficiency as well as the color oit the light in the case et vapor lamps. The diiiiculty of sealing leading-in conductors vacuum-tight into this material, however, heretofore have restrictedi its use.

My invention enables conductors capable ot carrying lvery heavy currents to be sealed into evacuated quartz apparatus, or, in general, into apparatus consisting of a material not suited to have conductors embedded therein by fusion.

ln accordance with my invention, hollow metallic caps are tightly fitted by means of a ground joint to the material ot the container and a column of mercury is interposed between the interior of the container and the interior of the cap or closure, so that, if any leakage should take place through the ground joint, or through the material of the cap itself, it is prevented from reaching the are chamber by the column of mercury, and

hence it is necessary that the gas pressure in the hollow cap become suiliciently great to overcome the weight of the mercury column before any gas can reach the arc chamber itself.

My invention may be best understood by reference to the following description taken in connection with the accompanyingdrawing1 which shows a halt' wave mercury rectifier illustratingthe invention. rlhe envelop l oi this rectiier, consisting of fused silica,in closes a cathode chamber 2, into which opens a condensing chamber 3 and a main anode chamber 4C. rlhe cathode chamber contains a puddle of mercury 5 constituting the cathode of the rectifier. The anode chamber'- contains an anode 6 consisting of graphite, or other refractory conductive material. The device is also provided with an auxiliary, or starting anode, 7, which is employed for maintaining` a continuous side branch, or exciting arc which hinctionates to maintain the rectifier alive between the successive halt` waves, or impulses ot current, in manner wellunderstood in the art.

ine cathode closure, or seal, consists of a metal cap 8 consisting', tor example, of iron,

and which is provided with a rentrant portion 9 projecting' into the neck l0 ot the envelop. "ihe cap 8 is tightly tit-ted by means of a beveled ground joint ll to the material of the container. The chamber l2 et the metallic cap and the annular space between the reintrant portion 9 and the wall of the container is filled with mercury which is continuous with the pool ott-mercury orming the cathode of the device.

lt will be observed that any leakage of air through the ground joint 1l or through the material of the cap due to any porosity must first force the mercury in the chamber l? up into the annular space between the portion 9 of the seal and the wall oit the container. and, as the wall of the container projects nearly to the bottom of chamber l2, t.1 is chamber must first be lled with a considerable amount ot gas before the gas can reach the mercury column upon the inside of the container wall. As the differences of pressure are compensated by the resulting differences in mercury level the pressure in the cap becomes greater than the weight of this column oi mercury before any gas can reach the interior of the rectifier. rlhe me chanical joint can be made very tight and the leakage will be so small that the life of. the joints will be many thousands of hourr.` and will exceed the life of the rest of the device.

rlhe anode seals are very similar in their construction. ln this case the lip of the container is provided with annular trough i3, the outer wall la of which extends beyo'nd the lip orn the container. The cap l5 is iitted to this wall le by means of a ground joint, as already described.. rlhe cap l5 is hollow and is provided with a rentrant portion 16 similarly to the cathode cap and is also provided with a downwardly projecting annular wall 17, which projects into the annular trough 13. When the container 1 has beenl evacuated and sealed ed inthe usual manner, thev annular trough 13 is filled with mercury by means of a small tube, the sealed portion of which has been indicated at 18. This mercury extends from the level 19 to the level 20, on both sides of the annular wall 17. The rentrant portion 16 has the anode 6 screw-threaded thereon1 and it is provided with a sheath 21 of refractory insulating material, such as silica, to prevent. the arc from extending upward beyond the anode 6.

rllhe metallic closure for the supplemental anode 7 is similar to that al-ready described in connection with'the main anode 4. Because of the smaller currentcarrying capacity required of the supplemental anode, a metallicstem 22, extending from the r upper wall of the cap 23, takes the place of the reentrant portion 16 of the cap 15. The downwardly depending tube 24l dips into mercury in the trough 25, thereby interposing a column of mercury between the interior of the container 1 and the interior of the anode cap. It will thus be seen that in the case of each anode seal, balanced columnsof mercury separate the space in the rectifier from the space in the hollow cap, and as already explained gas cannot enter the rectiieruntil the leakagepressure exceeds the weight of the mercury column seal.

What I claim as new, and desire to secure by Letters Patent of the United States, is,-

1. An evacuated container having a portion thereof closed by a seal comprising communicating columns of liquid of low vapor tension, and a mechanical closure for that portion of the seal which is external to the container, whereby the atmospheric pressure upon the liquid seal is reduced `to negligible amount.

2. An evacuated container having a closure therefor formed of balanced columns of mercury, and an external vessel closing the mercury column seal from exposure to` atmospheric pressure, said external vessel being likewise more or less evacuated.

3. A quartz receptacle provided at one part with an annular trough, fluid in the trough, and a closurefor the receptacle formin'ga ground joint with the quartz re'- ceptacleand dipping into the fluid in said trough, said closure being evacuated whereby the fluid columns separating the quartzreceptacle and the closure are of approximately equal heights.

tainer, a hollow, evacuated, mechanicallyfitted closure therefor, a body of mercury sealing t-he space in said container from thc space in said closure and a partition separating said mercury seal into two columns, communicating respectively with the container and the closure whereby gas pressure in the closure due to leakageis compensated by a change of mercury level, and is prelvented from entering the. space in the main container.

In witness whereof, I have hereuntov set my hand this tenth day of December, 1910.

EZECHIEL WEIN TRAUB. A Witnesses:

JOHN A. MCMANUS, Jr., CHARLES A. BARNARD.

4. The combination of an evacuated con- 

